PVC foam products - Unbalanced characterization of various auxiliaries (2)

Last article we introduced the first three kinds of additives in PVC foaming products, in this article Qingdao Sainuo lubricating dispersant manufacturer continue to look at a few auxiliaries.

4. Calcium powder

Foamed products generally choose the particle size of about 1200 mesh of light calcium is appropriate, calcium powder easy to moisture and formed on the surface of products, such as bubbles, silver, affect the appearance and physical properties, so pay attention to the rainy season storage.

(1)When the particle size of calcium carbonate is too large, it is easy to mix unevenly, the plasticizing time of the mixture is delayed, and the screw torque is low;

(2)When the particle size of calcium carbonate is too small, it is easy to agglomerate;

(3)When the dosage of calcium carbonate is too small, the number of foam cells and the foaming rate decrease;

(4)When the dosage of calcium carbonate is too much, the relative content of resin in the component is reduced, the melt strength is reduced, and the plate section is easy to be broken.

5. Foaming regulator

Foaming regulator generally refers to the viscosity of more than 10 acrylic processing aids, including eco-wood, Wainscot and other wood-plastic foaming products generally use the type of rapid plasticization, foaming Board especially Cabinet Board general selection of plasticizing slow melt strength of foaming regulator.

(1)The foaming regulator is insufficient, the melt strength is poor, the foam hole is uneven, the cross-section will appear the foam hole, the density increases;

(2)The foaming regulator is too much, the melt strength is too big, the bubble in the melt can not expand, the product density is high, the plate surface is easy to appear the ripple, the distortion and so on;

6. Foaming agent

The most used foaming agent is AC yellow foaming agent and NC white foaming agent, AC will give off a lot of heat during the decomposition process, resulting in products yellowing, and decomposition will have a small amount of ammonia; NC will absorb heat during the decomposition process, and decomposition tasteless, therefore, in foaming products, these two foaming agents will be used in coordination.

(1)The dosage of foaming agent is insufficient, the foaming rate is low, the product has few foam holes and the density is large;

(2)If the amount of foaming agent is too much, the melt strength will become low, the products will be difficult to form, and the cross-section of Foaming Board will be easy to form bubbles;

(3)Yellow foaming agent more, less white foaming agent, section prone to large and round foam.

Therefore, the dosage of various auxiliaries has a relationship of degree and mutual restriction. It is neither too little nor too much is not good. In production practice, it is necessary to go through repeated tests to give full play to the coordination effect of various raw materials and find the best balance point, fully improve melt strength and foaming efficiency, extend the start-up time.

Qingdao Sainuo Chemical Co.,Ltd. We are manufacturer for PE wax, PP wax, OPE wax, EVA wax, PEMA, EBS, Zinc/Calcium Stearate…. Our products have passed the REACH, ROHS, PAHS, FDA testing.

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